Facts about Phosphorus1 Nancy J. Gal and Wendy J. Dahl2
• maintain normal kidney function How much phosphorus do we need? Recommended Dietary Allowances (RDA) for phosphorus intakes are listed in Table 1. Because high intakes of phos- phorus pose health risks, Tolerable Upper Levels known as ULs have also been set to prevent overconsumption. Average daily intakes of phosphorus should not exceed the UL. Table 1. Recommended dietary allowances and tolerable upper levels for phosphorus (IOM 1997). Life Stage RDA UL (mg/day) (mg/day) Figure 1. Model of phosphate group Children Credits: Jan Kaliciak/iStock/Thinkstock, © Jan Kaliciak 1 to 3 years 460 3,000 Why do we need phosphorus? 4 to 8 years 500 3,000 9 to 18 years 1,250 4,000 Phosphorus is a mineral found in every cell of the body, Adults usually in the form of phosphate. It is the second most 19 to 70 years 700 4,000 abundant mineral in the body after calcium. About 85% of > 70 years 700 3,000 phosphorus is stored in the bones and teeth. It is important for forming bones and teeth, as well as repairing bones. Pregnant Phosphorus also helps: 14 to 18 years 1, 250 3,500 19 to 50 years 700 3,500 • promote normal muscle and nerve function Lactating • regulate heartbeat 14–18 years 1,250 4,000 19 to 50 years 700 4,000 • support growth and repair of cells and tissues mg = milligrams • store and use energy from food
1. This document is FSHN13-13, one of a series of the Food Science and Human Nutrition Department, UF/IFAS Extension. Original publication date November 2013. Revised May 2017. Reviewed January 2018. Visit the EDIS website at http://edis.ifas.ufl.edu.
2. Nancy J. Gal, Extension agent, UF/IFAS Extension Hillsborough County; and Wendy J. Dahl, assistant professor, Food Science and Human Nutrition Department; UF/IFAS Extension, Gainesville, FL 32611.
The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county’s UF/IFAS Extension office.
U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension. What is the availability of What happens if we get too much phosphorus in our diet? phosphorus? Phosphorus is abundant in our diet. The three main sources Excessive intake of phosphorus is much more common of dietary phosphorus are food and beverages, food addi- than inadequate phosphorus intake. Too much in the diet tives, and supplements. The main natural food sources are may lead to adverse effects on bone, kidney, and heart protein-rich foods such as meat, poultry, dairy products, health (Calvo and Uribarri 2013b). High blood levels eggs, legumes, and nuts. They provide about half of our of phosphorus are usually the result of consuming large dietary phosphorus (Calvo and Uribarri 2013a). Manufac- amounts of dietary phosphorus with insufficient dietary turers add phosphorus to many processed foods to modify calcium. Kidney disease can also lead to an excess of texture, taste, and color. Phosphorus added during food phosphorus. If you have chronic kidney disease, you may processing contributes an average of 500 mg/day (Calvo need to limit your intake of phosphorus (CDC 2012). As and Uribarri 2013a). kidney function decreases, extra phosphorus builds up in the blood. When there is too much phosphorus in the Because phosphorus is readily available in the diet, most blood (hyperphosphatemia), calcium is lost from bones people do not require phosphorus supplements. However, and deposited in tissues. This can lead to weak bones and many supplements and medications contain phosphorus. cardiovascular disease. Persons with chronic kidney disease For example, multivitamins and minerals contain, on should consult their health care provider for specific dietary average, more than 100 mg/supplement (Calvo and Uribarri recommendations. 2013a). Many over-the-counter and prescription medica- tions also contain phosphate salts as inactive ingredients In healthy individuals, mildly elevated phosphorus levels (Calvo and Uribarri 2013a). are thought to increase risk for bone and heart disease (Calvo and Uribarri 2013b). For most persons, reducing What happens if we do not get excess dietary phosphorus can be achieved by reducing consumption of processed foods that contain added enough phosphorus? phosphorus. For example, processed foods that may contain Phosphorus is plentiful in the typical American diet, and so phosphorus additives include pancakes from a mix, frozen deficiency is rare. However, certain health conditions such waffles, bacon, processed cheese, deli meats, and poultry, as starvation, alcoholism, and diabetic ketoacidosis can convenience dinner entrées, canned soups, and most cause low phosphorus levels. Also, certain medications such restaurant and fast foods. Additionally, cola beverages as some antacids and diuretics can cause phosphorus levels contain phosphoric acid, a form of phosphorus. The key to to decline (IOM 1997). The following are possible signs of lowering dietary intake of added phosphorus is to prepare low phosphorus in adults*: foods from scratch from fresh, unprocessed ingredients.
• poor appetite Unfortunately, the phosphorus content of food is not found on the Nutrition Facts Panel, making it difficult to • muscle weakness determine which foods are higher in phosphorus. However, • poor coordination the ingredient list on the food package is very useful when • bone pain making healthful food choices. Read the ingredient list on the food package to determine if the food contains a • fragile bones phosphorus/phosphate additive (Table 2). Ingredients are The following are possible signs of low phosphorus in listed from most abundant to least abundant and additives children*: are noted toward the end of the list. Avoiding foods with phosphate additives can help to lower your intake of • decline in growth phosphorus. • poor bone and tooth development Individuals with chronic kidney disease should seek profes- *Note: These may be signs of other disease conditions sional dietary advice regarding their diet choices. If you have questions regarding high- and low-phosphorus foods and would like to find a registered dietitian (RD) in your area, you can visit the Academy of Nutrition and Dietetics RD Finder at http://www.eatright.org/programs/rdfinder/.
Facts about Phosphorus 2 Table 2. Common phosphorus additives in processed foods. Aluminum Phosphate Pyrophosphate Dicalcium Phosphate Sodium Phosphate Hexametaphosphate Sodium Polyphosphate Monocalcium Phosphate Sodium Tripolyphosphate Phosphoric acid Tetrasodium Phosphate Polyphosphate Trisodium Phosphate Where can I find more information? Registered dietitians may be able to provide you with more information about choosing a healthy diet. Consult your pharmacist and physician with questions about medications and supplements.
The Family and Consumer Sciences (FCS) agent at your local UF/IFAS Extension office may have more information about food and nutrition and may have classes for you to attend. References Calvo, MS, and J. Uribarri. 2013. “Contributions to total phosphorus intake: all sources considered.” Semin Dial, 26(1): 54–61.
Calvo, MS, and J. Uribarri. 2013. “Public health impact of dietary phosphorus excess on bone and cardiovascular health in the general population.” Am J Clin Nutr, 98(1): 6–15.
CDC (Centers for Disease Control and Prevention). 2012. http://www.cdc.gov/diabetes/projects/pdfs/ckd_factsheet. pdf
IOM (Institute of Medicine). 1997 http://www.nal.usda.gov/ fnic/DRI/DRI_Calcium/146-189.pdf
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